The U.S. weather pattern is stuck in a rut. Here's why.

I’ll tell you right now that I tricked you with the title. When you read “Here’s why”, you probably thought I would give you a simple one-sentence answer. Yes, just one sentence could explain how the east coast has been pounded with snow for over a month while the west coast is sacrificing new animal species in hopes of seeing a few flakes.
This weather pattern that is gripping the U.S. during the early part of 2011 is cut and dry, but the explanation for the pattern is anything but. The atmosphere is more complicated that a teenage girl, so a simple explanation about the current weather pattern is just impossible. But here are a few tid bits that you can internalize and use to impress your friends:
• Stable = Good. When things in your life are stable and predictable, it’s generally less stressful than when things are all over the place and changing by the hour. A stable situation not only feels good to people, but also to the atmosphere. When a weather pattern is stable, it takes a good deal of force to change it up. For the last 4-6 weeks, the atmosphere has enjoyed dumping snow on the east coast, throwing occasional storms to Montana, Wyoming, and Colorado, and keeping the west coast dry. If the atmosphere is happy and stable, why change?
• This isn’t unusual. Al Gore and other scientists were quoted this week saying that global warming caused the recent storminess on the east coast. Nope. I bet we could go back and find weather records over the last 50+ years and find similar periods of time where snow kept piling up on the east coast. As a native of the Philadelphia area, I can remember a few winters with consistent snowfall. Global warming (better name: climate change) may eventually affect some aspects of our weather, but attributing the weather pattern over the last 4-6 weeks solely to global warming is just not true. I wish that science were that simple, but it’s not.
• The details matter. While it is easy to say “snowy in the east, dry in the west”, once again it’s not this simple. The overall weather pattern is this simple, but the details change from storm to storm. Slight variations in the track of each storm determine weather certain spots see light snow, big dumps, or nothing at all. Some computer weather models are forecasting this general weather pattern to persist for another 10 days, but specific forecasts – snow amounts for your mountain – are impossible to make 10 days in advance. Little changes or wiggles in the Jet Stream (see image) can make or break a powder day. Understanding the overall weather pattern is nice, but pay more attention to the details of each storm.
Yes I know, leave it to a meteorologist to use three bullet points and hundreds of words to offer an answer to a very simple question like “Why is our weather pattern stuck in a rut?” We’ve been conditioned to believe all things can be explained easily and quickly, but often that’s not true at all.
Hopefully my more nuanced answer makes sense and gives you something to mull over. If it were up to me, though, I’d just create a weather machine that produced powder over all mountains every other day. Then we could spend less time on complicated weather patterns and just go get lost in the white room.
Meteorologist Joel Gratz is the creator of http://www.ColoradoPowderForecast.com and is based in Boulder, CO.

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